System of control



March 4 1924. 1,485,431

R. RUDENBERG SYSTEM OF CONTROL Fi led Dec. 15. 1920 Patented Mar. 4, 1924.

UNITED STA REINHOLD RIlDENBERG, or B nLm-eR NEwaLn, GERMANY, nssreuon To SIEMENS scnvcxrnmwnnxn e sn LscnAr-rr MIT nnscnnnivmnce HAFTUNG, or SIEMENS- s'mnr, NEAR BERLIN, GERMANY, A GERMAN conrom'non.

s Ys'rmi or common.

Application filed fieehibe i 15, 19in. Serial no; 431,651.

To all whom it may cont-em; i N p Be it known that I, Rnnvnom Riinnivnnnc; a citizen of the German" Empire, residing at Berlin-Grunewald, Germany, have invented certain new and useful Improvements Systems of Control, of which the following is a specification. I I

My invention relates to protective arrange ments for dynamo-electric machines, and particularly to arrangements for protecting such machines from operating at too high speeds. i

In the operation of electric generators of great output special precautionary measures 5 are required for protecting the machines against any undue increase of speed such as may take'place whenever at excessive loads in the system the overload circuit breaker is actuated and cuts out the electric energy. Since the supply of motive lower suchja's steam, liquid fuel, the electric current the like to the driving motor or prime mover is at first decreasing only slowly, it will cause the speed of the generator to rise. In order to avoid any undue increase of speed, a rapid closing valve adapted to be actuated by the governor of the prime moverhas been preposed to be inserted in the supply of motive power to the prime mover. I p 7 Experience has shown that such rapid closing valves are apt to undergo detrimental changes under the influence of the h temf perature of the steam. They are l able to warp and, in consequence th'ereof, to stick fast or to effect only imperfect closu re, thus leaving the supply of'energy to the prime mover partly uninterrupted v The prime mover as well as the generator are subject thereby to great damage. 7 i I According to my invention I avoid this drawback by providing a safety arrangement doing away with the causes forracing of the machine and thereby rendering the machine in most cases independent from the state and conditions of working of the rapid closing valve. I propose to take care of interrupting the supply of energy to the gener= ator before the generator main switcli is opened. I prefer interrupting the supply 0 motive power to the prime mover imme diately before opening the main switch thus causing the energy to be decreased already when the generator rfiain switch is opened, and I therey avoiding eirythifig which might form a cause for the racing of the ma i e; In om c i l Hab P fer decreasing at the same time the" eicit'er energy of the generator. I

U myinve'ntion into practice I may. P oceed arm was, u in n cases I obtain the advantage of absolutely protecting the prime mover as well as the generatorfrom the mechanical risks of racmg; This is the more important as in modern machines of this; kind inasmuch as thestress placed upon them is already so high that the admissible maizimum increase of velocity of about 15 cent constitutes the admissible maximumstress on the difierentpartsj of theniachine.

.I eutain the very iitipdttant advantage of beir'ig able o disconnect the electric generator an absolutel iinner gizeds'tate; avoidiri antke ificultie's, which have to dealt wit generally in high power switches. The turbine or other prime mover is prevented from any more energy to the switch are; on the other hand a I'EtClIig of the turbine after the main switch is "ened is re eredim p ssible from the beginnifig, and thereforet e. switch as well as on the machine are ab? solfltely protected roma mechanical as well as from electrical point of view.

7 order to can dff 'thesupply of energy fo e waning die fieiat main s t I refer employing the releasing niechariisiri o generator main switch ltsel-f, which actuated either the maximum current or rever'sal r empt onbythe drop in voltageor some other safety device for excess voltage pretection or, the like, the valve of the motive power supplybeing coupled with the said releasing nn'achanisn'i either mechanically orelectrically in such a manner that the valve-movement leads the switch movement proper. consequence thereof when the main switch is closed no matter from what causes the motive" power su ply is starte' while befdre the main switc h is dpfi au e rbwer u p s e rupted cjausin'g reli'ay acting iipon' the em swab a e src aii ler t m viously upon the motive power supply. he

main switch as well as the rapid closing device required as a safeguard against an undue increase in speed may be made to act through their releasing mechanisms upon the same stop valve for the same motive material supply. However, besides the rapid closing valve a special valve may be provided for regulating the motive power sup-- ly. P In the drawings accompanying this speci-. fication and forming part thereof the preferred form of an arrangement in accordance with my invention is shown in a purely diagrammatic manner.

a is a steam turbine and b is the electric generator driven by it. a is the field winding of the generator fed from the continuous current mains (Z over a regulator e. f is the rapid closing valve actuated from the governor h by means of the ratchet gear g. i is a valve for controlling the steam supply from a boiler is to the turbine a.

In order to start the generating set an auxiliary valve Z arranged near valve 91 and also the rapid closing valve are opened, admitting steam into the turbine in a quantity sufiicient to preheat it and to start it at full speed. As soon as this is effected the generator is synchronized and the main switch m is closed. lVith the main switch is coupled a switch 71 adapted to close a circuit for controlling the energy supply. Valve 2' may be actuated for instance by a repulsion motor 0. Its exciter winding p is then closed and supplied from the circuit 7' over switch a and wire 8 so that the motor moves in a valve opening direction, switch a being assumed closed at that time.

Valve z' is now opened and full steam is supplied to the turbine. As soon as the valve is opened completely the end switch a is opened by suitable means not shown here, so that the motor 0 stops operating. The auxiliary valve Z may now be closed either by hand or by other suitable means.

In case an unduly large current is now generated, it will flow through the maximum releasing mechanism a: of the main switch as well as through another relay y, requiring less time to act than main switch 03, which latter is controlled by suitable retarding means, for instance dash pot D. Relay 3/ when energized lifts the contact plate 2 which is permanently connected to circuit r and closes the circuit of auxiliary motor 0 by means of the exciter winding 9 such that this motor now runs in valve closing direction. The closing operation is continued until the end switch '0 is opened by suitable means not shown here. At the same time also circuit 1, 2 is supplied with current from the system and starts a motor 3 coupled by a suitable clutch. connection not shown with the regulator e of the generator field c in such a manner, that the motor will act upon the regulating resistance only in the case where it is desired to decrease the exciter energy for the cutting out of the generator. The motor therefore connects the regulating resistance in series and thus diminishes or renders ineffective the generator field. At the same time the maximum releasing mechanism a' releases the stop 25 and the main switch as well as the circuit of auxiliary motor 0 controlling the openin of the steam supply valve, to be opened. t is not necessary, of course, to operate the whole system by electrical means. If it is desired to throw the generator out in 21 normal way it is possible to close also the circuit for the closing movement of the steam supply valve so as to decrease the steam supply and the exciter energy of the generator before the main switch acts.

In the system described above the exciter energy is diminished by means of the motor 3 by placing an increasing resistance in series with the exciter winding. It is also possible to cause the releasing coil of the maximum switch a" to place a high resistance in the exciter circuit for instance by opening by means of the relay a short-circuiting device which shunts the said resistance during the normal working of the generator.

I claim:

1. The combination with an electric generator and a prime mover driving it, of a generator main switch, means connected in circuit with said switch for causing the interruption of the supply of energy to the prime mover before said switch is opened and means operatively connected with said switch for controlling the supply of motive power to the prime mover, when the main switch is closed.

2. The combination with an electric generator and a prime mover driving it, of a generator main switch and means in circuit with said switch for causing the interruption of the supply of motive power to the prime mover before releasing said switch.

3. The combination with an electric generator and a prime mover driving it, of a. generator main switch, mechanism for re leasing said switch and separate means for interrupting the motive power supply to the prime mover before said switch is released.

4. The combination with an electric generator and a prime mover driving it, of a generator main switch, arelay for releasin said switch and another relay suitably timed to act before said releasing relay for interrupting the supply of motive power to the prime mover.

5. The combination with an electric generator and a prime mover driving it, of a generator main switch, mechanism for releasing said switch, means for interrupting the supply of motive power to the prime mover before said main switch is released and means, controlled by the operation of time, means for interrupting in less time the i said interrupting means for controlling the supply of motive power to said prime mover excitation of said generator. and means, controlled by the operation of a 6. The combination with an electric gensaid interrupting means for cutting out the 5 erator and a prime mover driving it, of a. BXOltflUOI} 0f 831d generator generator main switch, mechanism for re- In testlmony whereof I E y slgnatul'eleasing said switch within a predetermined REINHOLD RUDENBERG. 

